Interesting post, but this is wrong:
Australia dithering leaving NATO to avoid complete economic meltdown when they suddenly can't sell their mining produce to it any more
Australia realised during World War 2, that they were completely dependent on the US to be able to prevent invasion and occupation of Australia from Japanese forces. Since then they a strategy of doing everything that the US wants, to retain the strong military alliance between them.
Although it would hurt massively in the short term, I can't see _anything_ that would break that alliance. It would basically be a declaration that Australia would be prepared to become allied with and accepting military occupation by China.
And it would just be the short term - if there was a military conflict with China that shut down trade, having several hundred million people suddenly unemployed in China would cause a faster change in government there than not being able to buy the latest iPhone or more plastic crap would in the US and Australia.